In some service utilizing systems in the past, the terminal management servers connected to a network are designed to identify individual terminal devices and to manage various kinds of information about them (refer to the patent document 1 for example).
In such a service utilizing system, a different ID (Identification) is given to each terminal device and is stored in its nonvolatile memory. When a terminal device communicates with various kinds of servers through the network, it sends its terminal ID to the servers.
The terminal management server of the service utilizing system is designed to identify each device with its ID sent from it and to communicate with it.    Patent Document 1: Japanese Patent Laid-Open No. 2003-85145 (P5; FIG. 1)
The service utilizing system in such a configuration, however, requires extra work to store a different terminal ID in each terminal device as well as the management of the terminal IDs of all the terminal devices by the terminal management server.
The terminal management server, therefore, needs to frequently update the terminal IDs under its responsibility in order to support all the terminal devices manufactured successively in the factories, which required extra work to operate the terminal management server and complicated the configuration of the service utilizing system as a whole.
Furthermore, the terminal ID was comprised of the combination of alphanumeric such as “ABC12345”, which was easy for the terminal management server to identify a terminal device but was hard for the user to become familiar with and to identify it.